Accumulated Other Comprehensive Income - Summary of Accumulated Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 6,607	$ 7,296
Reclassification for gains included in net income	1		(111)
Current year changes	(2,693)	1,292	(3,025)	509
Ending balance	3,582	7,805	3,582	7,805
Unrealized Gain (Loss) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(23)	856
Current year changes			1,204	(735)
Ending balance	1,181	121	1,181	121
Unrealized Gain (Loss) on Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			6,630	6,440
Reclassification for gains included in net income			(111)
Current year changes			(4,118)	1,244
Ending balance	$ 2,401	$ 7,684	$ 2,401	$ 7,684